Russian knapweed (Acroptilon repens)

  • Russian Knapweed Plant 215x150

Category B Weed

Sunflower family (Asteraceae)

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  • Numerous; highly branched, stiff, 1-3 ft. tall and covered with wooly gray hair; NO wings


    • Alternate; mostly covered with wooly gray hair

    • Lower leaves 2-4 in. long with lobed to wavy edges (margins); upper leaves strap-like (linear) or lance-shaped and less than 1.2 in. long with smooth or toothed edges


      • Purple, pink or white, each located at the tip of a branch; base of flower is vase-shaped, 0.25-0.5 in. wide and covered with green bracts with papery or whitish edges


        • Creeping root system; upper roots often dark brown to black


          • Grows well on a broad range of sites; often found in rangeland, waste areas, roadsides and along waterways; known to occur in all Nevada counties

          • Perennial; reproduces by roots and seed

          • Causes "chewing disease" in horses by damaging the area of the brain that controls fine motor movements, particularly of the mouth; results in starvation or dehydration


            • Mowing and tillage are NOT effective

            • Apply glyphosate, chlorsulfuron or clopyralid from the bud to flower stage; aminopyralid or picloram from bud through dormancy; imazapic to dormant plants in fall


              Russian Knapweed Investation 215x150
              Russian Knapweed Plant 215x150
              Mature Plant
              Russian Knapweed Flower 215x150
              Russian Knapweed Rosette 215x150
                Nevada Noxious Weed Field Guide
              Nevada Noxious Weed Guide